BT Posted a lot   Posts: 1,772 | SOLVED - No Spark, Coil Gets Power, Porsche 944. BT @radfax | Jun 19, 2016 12:15:30 GMT - Select Post
- Deselect Post
- Link to Post
- Back to Top
| | Hey chaps. I am in need of some superior guidance and advice in regards to a problem I am having with a 1983 Porsche 944 of the 2.5 manual variety. I've got the car cranking over but am failing to get a spark, however my cool is being provided with suitable power. I have my own suspicions here, but would just like to hear some other opinions on the matter before I spend any substantial amounts of cash. So, a quick run down. Car battery is showing 12.6V + side of the coil shows 12V - side of the coil shows 12V Yet no spark is coming out of the coil. I have tested the resistance on the coil and have had the following results. Primary, which is between the + and - terminals is showing at 1ohms and should be between 0.5-0.7. Secondary is between terminal 15 and terminal 4, which is either the +/- and a terminal hidden under a rubber Bung at 12 o'clock on the coil. Well the rubber Bung has been pushed into the void and I have been unable to test this terminal, despite fishing the Bung out. I have however tested between the HT output and the advised terminal. Secondary resistance should be between 7.5-5.5 and when I test the way I have been I am getting 5.4ohms. If I connect a jump pack to the + terminal and the block I do get a very weak spark. Is it a fair assumption that this coil is past it? I would usually replace one because previously they've been very cheap, but for this specific model they've proved quite expensive, so obviously don't want to go and throw good money after bad. If it makes any difference, I also can not hear the fuel pump prime. I do wonder if the coil and the pump is shagged, but have even started to wonder if it is some sort of aftermarket or even factory immobiliser. I have no idea and any help or advice would be absolutely fantastic. Thanks very much. | | Last Edit: Jun 21, 2016 20:56:04 GMT by BT |  Reply Quote | |
Porsche West Midlands  Kev from B'ham. Posts: 4,725 | SOLVED - No Spark, Coil Gets Power, Porsche 944. Porsche @porsche | Jun 19, 2016 12:32:05 GMT - Select Post
- Deselect Post
- Link to Post
- Back to Top
| | 1st, try changing the DME relay. A common problem with Porsche 944s. (And a cheap/easy fix). | Last Edit: Jun 19, 2016 12:33:11 GMT by Porsche  | | Reply Quote | |
| BT Posted a lot Posts: 1,772 | SOLVED - No Spark, Coil Gets Power, Porsche 944. BT @radfax | Jun 19, 2016 12:48:34 GMT - Select Post
- Deselect Post
- Link to Post
- Back to Top
| | Nice one mr Porsche! I'll get reading on that! | | Reply Quote | |
| BT Posted a lot Posts: 1,772 | SOLVED - No Spark, Coil Gets Power, Porsche 944. BT @radfax | Jun 20, 2016 16:28:37 GMT - Select Post
- Deselect Post
- Link to Post
- Back to Top
| | I made up a 3 wire jumper and my DME relay is shagged. If I jump the relay board I do get the fuel pump prime, however still no start. My ignition switch is faulty, if I turn the key it lights up the dash but does not actually turn the motor over, I have bypassed this with an ignition button. I am wondering if the no spark could be related to a faulty ignition switch? I have asked my parts supplier for a price on a coil, but I'm not looking forward to hearing what it's going to be. | | Reply Quote | |
welshpug Posted a lot  Posts: 4,456 | SOLVED - No Spark, Coil Gets Power, Porsche 944. welshpug @welshpug | Jun 20, 2016 16:51:05 GMT - Select Post
- Deselect Post
- Link to Post
- Back to Top
| | got any pictures of the coil etc? which injection/ignition system is it?i know a few of the bosch systems as peugeot used a few quite similar to Porsche and vw. | | ZX 16v, 205 GTI. my ZX's project thread - retrorides.proboards.com/thread/151997/16v-project-pt2-power-upgrades | | Reply Quote | |
colnerov Posted a lot  Posts: 2,983 | SOLVED - No Spark, Coil Gets Power, Porsche 944. colnerov @colnerov | Jun 20, 2016 17:15:11 GMT - Select Post
- Deselect Post
- Link to Post
- Back to Top
| | Hi, You have 12v to the coil, if you put a spark plug on the king lead and lay it on the engine then run a fly lead from the negative term on the coil to earth does the plug spark? If yes then move on to the dist, if no then it looks like the coil is faulty. Colin | | Last Edit: Jun 20, 2016 17:16:17 GMT by colnerov | | Reply Quote | |
ChasR RR Helper  motivation Posts: 10,442 Club RR Member Number: 170 | SOLVED - No Spark, Coil Gets Power, Porsche 944. ChasR @chasr Club Retro Rides Member 170 | Jun 20, 2016 17:44:45 GMT - Select Post
- Deselect Post
- Link to Post
- Back to Top
| What Colnerov said  .The dizzy caps tend not to get replaced as often as they should, partly down to the cost. | | 1979 Honda NC-50'03 BMW M3 Coupe2016 Yamaha XSR7002025 Renault 5 Techno ComfortMy car history and exploits:leylandlegends.com | | Reply Quote | |
| BT Posted a lot Posts: 1,772 | SOLVED - No Spark, Coil Gets Power, Porsche 944. BT @radfax | Jun 20, 2016 20:50:40 GMT - Select Post
- Deselect Post
- Link to Post
- Back to Top
| | Thanks very much for the replies, I'm currently replying from bed after giving up for the evening so please forgive the shortness of this reply. Injection system I seem to think is Kjet, similar to VW items. Ignition wise I have no idea, I shall investigate and report back. Thanks for the tip on the coil and the negative, I will try that tomorrow evening once I am home from work. The dizzy when I got the car seemed to be incorrectly fitted and didn't look at its best, but I was putting the fault down to the coil and didn't investigate the dizzy set up with much passion. Since my last reply I have installed a new ignition switch which seemed simple enough and now I get the engine cranking over on the key, I thought this may have been playing a part in the DME relay but still no difference. With further investigations I have possibly found another avenue to persue. I get no taco bounce what so ever on cranking, needle is dead flat and it should supposedly bounce. This seems to suggest the problem is in the speed reference sensor or sensors on the rear of the engine. Annoyingly the sensors are super expensive but I've found the part numbers are the same as E30 crank sensors which are a lot more affordable. | | Reply Quote | |
| ChasR RR Helper motivation Posts: 10,442 Club RR Member Number: 170 | SOLVED - No Spark, Coil Gets Power, Porsche 944. ChasR @chasr Club Retro Rides Member 170 | Jun 20, 2016 20:57:21 GMT - Select Post
- Deselect Post
- Link to Post
- Back to Top
| | IIRC the 944s came with the Bosch Motronic system, not K-Jetronic . The sensors may simply need regapping, but I'd check for the spark first before chasing a red herring. | | Last Edit: Jun 20, 2016 21:01:21 GMT by ChasR 1979 Honda NC-50'03 BMW M3 Coupe2016 Yamaha XSR7002025 Renault 5 Techno ComfortMy car history and exploits:leylandlegends.com | | Reply Quote | |
| BT Posted a lot Posts: 1,772 | SOLVED - No Spark, Coil Gets Power, Porsche 944. BT @radfax | Jun 20, 2016 21:01:11 GMT - Select Post
- Deselect Post
- Link to Post
- Back to Top
| | Ah excellent mr Chasr! You are certainly right. I was reading a thread about a 924 on here and Kjet was mentioned. However whilst trying to hunt down some sensors They're coming back as Bosche Motronic items Just to add, my late night browsing seems to have turned up some fantastic sensor options! | | Reply Quote | |
| welshpug Posted a lot Posts: 4,456 | SOLVED - No Spark, Coil Gets Power, Porsche 944. welshpug @welshpug | Jun 20, 2016 21:50:38 GMT - Select Post
- Deselect Post
- Link to Post
- Back to Top
| | motronic makes things a bit easier, basically all reliant on a switched live powering up the ecu and coil, then if it sees crank signal it'll run the pump and fire an earth to the ignition amplifier and injectors.on motronic the tacho is usually driven from the ecu rather than the coil.unsure on the older kjet, but i know jetronic uses a sensor in the dizzy for an engine speed signal which triggers the ignition amplifier and also goes to the injection ecu and tacho. | | ZX 16v, 205 GTI. my ZX's project thread - retrorides.proboards.com/thread/151997/16v-project-pt2-power-upgrades | | Reply Quote | |
| BT Posted a lot Posts: 1,772 | SOLVED - No Spark, Coil Gets Power, Porsche 944. BT @radfax | Jun 21, 2016 20:55:22 GMT - Select Post
- Deselect Post
- Link to Post
- Back to Top
| Thanks for the help again welshpug. The 944 has two sensors on the top of the bell housing. One is a speed sensor, one is a refference sensor. From my research they are the same as a E30 crank sensor and therefore I assumed did the same as a crank sensor and without that signal I guessed it wouldn't fire. I ordered some new sensors last night and tonight I set about removing my current sensors so that I could Throw the new sensors straight in tomorrow. Upon removing the speed sensor I found this...  I cleaned what appears to be a little bit of rust off the end of the sensor that the magnet has picked up and attracted and tested it, 1050 ohms across two pins, 1M across the other two. This falls almost bang in the middle of the recommended resistance. With this in mind I then tested the resistance with the sensor pressed against the metal body work of my car, the resistance went way high, I then wondered if the magnetised bit of crud on the end of the sensor meant that the sensor was unable to relay the correct information back to the ecu and in turn ground the coil for a spark. I refitted the sensor just out of curiosity really, cranked it over with a 3 way DME jumper in the relay and it started straight up! The car has sat unused and has not been run for well over 3 years now, the DME relay was obviously a fault, as was a faulty ignition switch (which someone in the trade had diagnosed as a £330 starter motor, when in reality it was a £6 ignition switch) and I wonder if removal and testing of the starter motor has induced some sort of crud into the bell housing which has in turn been picked up by the sensor. Either way it now runs. I did however manage to dodge the £145 charge for each sensor, I actually managed to get the pair for £20 through cross referencing part numbers. So if anyone comes across this via the search function please PM me and I'll gladly share the part numbers so you can save a few quid. Thank you all very much for all of the help offered. | | Reply Quote | |
| ChasR RR Helper motivation Posts: 10,442 Club RR Member Number: 170 | SOLVED - No Spark, Coil Gets Power, Porsche 944. ChasR @chasr Club Retro Rides Member 170 | Jun 21, 2016 22:04:17 GMT - Select Post
- Deselect Post
- Link to Post
- Back to Top
| | If you could PM the numbers that would be great. I have to ask though, what brand are the sensors that you've ordered .Good news that you got to the bottom of it and hopefully for free . You have to love misdiagnosis eh? | | 1979 Honda NC-50'03 BMW M3 Coupe2016 Yamaha XSR7002025 Renault 5 Techno ComfortMy car history and exploits:leylandlegends.com | | Reply Quote | |
| nib3381 Kinda New Posts: 1 | SOLVED - No Spark, Coil Gets Power, Porsche 944. nib3381 @nib3381 | May 15, 2021 12:26:49 GMT - Select Post
- Deselect Post
- Link to Post
- Back to Top
| | Jun 21, 2016 22:04:17 GMT ChasR said:If you could PM the numbers that would be great. I have to ask though, what brand are the sensors that you've ordered .Good news that you got to the bottom of it and hopefully for free . You have to love misdiagnosis eh?Please can I have these part numbers as I have the same problem on an'82 944 lux. We have just changed the coil and change too the spark. Much appreciated.My email [email protected] | | Reply Quote | |
truckdoctor Part of things  P5b Coupe Posts: 555 | SOLVED - No Spark, Coil Gets Power, Porsche 944. truckdoctor @truckdoctor | May 15, 2021 18:49:38 GMT - Select Post
- Deselect Post
- Link to Post
- Back to Top
| | Jun 20, 2016 20:57:21 GMT ChasR said:IIRC the 944s came with the Bosch Motronic system, not K-Jetronic . The sensors may simply need regapping, but I'd check for the spark first before chasing a red herring.Definately remember working on a 944 with Bosch K jetronic. It needs a signal from the distributor before anything works. It must be the worst injection system to fix if its been sitting for years. | | Reply Quote | |
SOLVED - No Spark, Coil Gets Power, Porsche 944. 
Posts: 1,772 
Reply Quote 
Posts: 4,456 
Posts: 2,983 
.The dizzy caps tend not to get replaced as often as they should, partly down to the cost. 